Hardly unambiguously supporting heresy! The Pope was quite clear that he was commenting on Kaspar’s address the previous night, not on any of Kaspar’s far more problematic further comments. To be clear, Kaspar specifically renounced that evening many of the problematic proposals he earlier certainly seemed to be endorsing:
“[The Church] cannot propose a solution that is different from or contrary to the words of Jesus. The indissolubility of sacramental marriage and the impossibility of a new marriage during the lifetime of the other partner is part of the tradition of the Church’s binding faith that cannot be abandoned or undone by appealing to a superficial understanding of cheapened mercy...
“...It would be mistaken to seek the solution of the problem only in a generous expansion of the procedure of nullity of marriage. This would create the dangerous impression that the Church is proceeding in a dishonest manner in granting what in reality are divorces.”
Kaspar did raise proposals that the synod did not endorse, presumably because they are still problematic, but Pope Francis’ praise didn’t specifically endorse those proposals. Indeed, what would be the purpose of the synod if to praise the raising of a question could be equated directly with endorsing it as an answer?